The present invention relates to a new and distinct trailing blackberry variety designated as ‘HJ-7’. This new variety is a result of a controlled cross made by the inventors, Harold A. Johnson Jr. and Judith E. Johnson, in 2005 between the blackberry variety designated ‘Obsidian’ (female) and the blackberry variety designated ‘Eaton’ (male), both parental varieties unpatented. The variety ‘HJ-7’ is botanically known as Rubus ursinus. 
The seedling resulting from the aforementioned cross was selected from a controlled breeding plot near Watsonville, Santa Cruz County, Calif. in 2007 by the inventors. After its selection, the new variety was further asexually propagated beginning in October of 2007 in Watsonville, Santa Cruz County, Calif. by tissue culture. The new variety was then tested in fruiting fields in Santa Cruz County, Calif. This propagation has demonstrated that the combination of traits disclosed herein as characterizing the new variety are fixed and remain true to type through successive generations of asexual reproduction.